Engine operating temp of 185?

[SteveOO]

I recently bought a 1980 ericson 38 with the original Universal 5432 diesel with 4k hours, and I'm trying to decide if it has an overheating problem or not. The previous owners said the engine temperature gauge should be at 160f, but when I motor around it climbs up to 180-185 at 1800-2000 rpms (in cold PNW waters). I've check the raw water strainer, checked the impeller, and just installed a new 160 degree thermostat. I used a heat gun and the thermostat housing stays around 162, while the oil filter near the bottom of the engine is in the low 180s. Is that discrepancy normal, or too high? I haven't really kept pushing the engine once it creeps above 180, I don't want to cause any damage.

I guess next steps would be to check out the heat exchanger and the exhaust elbow? Or do I even have a problem? If I do look at the exhaust elbow as a culprit, what am I even looking for? I assume some sort of build up that impedes the flow of gas, but not sure.

Cheers.

Edit: I found the 5432 engine manual and it says 170-185 is a normal operating temperature, and I've found some threads on here where others run the same engine at 190 all the time. It's odd if it suddenly runs 25 degrees hotter than it allegedly used to though.

 

[Christian Williams]

Maybe he was talking about a 160-degree thermostat. 180 running temp is pretty much exactly perfect for the 5432.

I figure when the temp rises towards 190-200 at wide open throttle, it's time to clean the heat exchanger. Typically happens after maybe five years or so, and more or less to be expected as routine maintenance.

 

[SteveOO]

Maybe he was talking about a 160-degree thermostat. 180 running temp is pretty much exactly perfect for the 5432.

I figure when the temp rises towards 190-200 at wide open throttle, it's time to clean the heat exchanger. Typically happens after maybe five years or so, and more or less to be expected as routine maintenance.

Thanks for confirming that

 

[ConchyDug]

I'm kind of curious how others with the 5432 have their water heaters tapped into the engine coolant plumbing. Does everyone have a bypass loop installed? I've wondered how much this would effect higher rpm engine temps if the bypass is omitted. I would guess the heaters are fairly restrictive in their plumbing. Attached a couple diagrams to clearly show what I'm talking about. One is a Kuuma and the other a Raritan.

 

[SteveOO]

@ConchyDug Good point, I haven't found any bypass loop to the water heater on my setup

 

[Christian Williams]

My Previous Owner had an elaborate water-heater bypass--a cloud of bronze valves.

I took it out when I revised the cooling system and have had no issues.

Marine Diesel Cooling System Upgrade 2020

Symptoms: Apparent decrease in water volume at exhaust. Temperature RPM limitation at Wide Open Throttle. Steam from exhaust at idle. Solution: clean heat exchanger, optional general upgrade. When I took over Thelonious II four years ago, the boat would run at near seven knots all day at...

ericsonyachts.org

 

[ConchyDug]

What water heater do you have installed Christian? I have a Kuuma 6gal installed. I wonder if some have better flow thru vs others. My system doesn't have a bypass as well. Although it calls for one in the install guide, so I plan to add what is depicted in the second image I attached. It seems simple enough 2 tee fittings and a valve. My temp starts to reach 190 and beyond at higher rpms. I've done all the low hanging fruit maintenance. So now I'm thinking that maybe at higher rpms the belt driven coolant pump's flow rate is physically limited by the ID of the plumbing in the water heater.

 

[Christian Williams]

This boat has an Isotemp, but I put a Kuuma 6 in the 32-3 with no bypass and no problems.

It wouldn't hurt to install a bypass , although mystery shrouds all engine temps. Extended WOT probably leads to rising temps for almost everybody. Gradual increase over time often just means routine heater exchanger maintenance.

 

[Joliba]

I have no bypass in my 5432’s water heater loop and have no problem with overheating. I use a 180 degree thermostat and sail in Lake Michigan (sailing season water temperatures generally vary between 40 degrees F and 72 degrees F.)
Mike Jacker